Photographic material with polymeric stabilizers

ABSTRACT

A light-sensitive photographic silver halide material containing hompolymers or copolymers of 1,3-dihydroxy-2-methylene-propane or derivatives thereof which have an advantageous stabilising effect on the photographic properties of the silver halide emulsion layers.

United States Patent [191 Saleck et al.

[ Dec. 16, 1975 PHOTOGRAPIIIC MATERIAL WITH POLYMERIC STABILIZERS Inventors: Wilhelm Saleck, Schildgen; Helmut Engelhard, Dorrnagen; Wolfgang Himmelmann, Opladen; Francis Bentz, Cologne; I-Ielmut Mader, Odenthal-Hahnenberg, all of Germany Assignee: Agfa-Gevaert Aktiengesellschaft,

Leverkusen-Bayerwerk, Germany Filed: June 20, 1974 Appl. No.: 481,187

Foreign Application Priority Data June 27, 1973 Germany 2332562 US. Cl. 96/114; 96/109 Int. Cl. G03C 1/04; GO3C 1/34 Primary Examiner--Rona1d H. Smith Attorney, Agent, or FirmConno1ly and l-lutz [57] ABSTRACT A light-sensitive photographic silver halide material containing hompolymers or copolymers of 1,3- dihydroxy-2-methylene-propane or derivatives thereof which have an advantageous stabilising effect on the photographic properties of the silver halide emulsion layers.

5 Claims, No Drawings PHOTOGRAPHIC MATERIAL WITH POLYMERIC STABILIZERS This invention relates to a photographic material which contains at least one silverhalide emulsion layer, the stability of which has been improved by the addition of homopolymers or copolymers of 1,3-dihydroxy- 2-methylenepropane or derivatives thereof.

As is known, light-sensitive silver halide emulsions, particularly those which have been chemically sensitised, havea tendency to fog, i.e. to form nuclei which are capable of developing without having been exposed to light. Fogging occurs inparticular if the emulsions are stored too long, especially if they are stored at elevated temperatures and atmospheric moisture levels or if they are developed for too long or at excessively high temperatures. It may also be caused by certain additives, by excessive ripening of the emulsions, etc. The tendency of photographic silver halide emulsions to fog can to a certain extent be suppressed by the addition of so-called stabilisers or anti-fogging agents. Substances which have this effect are, for example, heterocyclic mercapto compounds or inorganic or organic mercury compounds.

These stabilisers, however, often have the disadvantage of reducing the sensitivity of the stabilised emulsions if employed at the concentrations at which they are effective and their usefulness is thereby limited. Moreover, the gradation of the emulsions may be deleteriously affected by the stabilisers.

It is an object of this invention to find stabilisers for photographic silver halide emulsions which are free from the disadvantages mentioned above and which have improved properties with regard to their resistance to fogging during prolonged storage or at elevated temperatures.

A light-sensitive photographic material containing at least one silver halide emulsion layer has now been found which contains homopolymers or copolymers of 1,3-dihydroxy-2-methylenepropane and/or l,3-dicarbamoxy-2-methylenepropane or derivatives thereof.

Compounds of the following formulae are particularly suitable stabilisers according to the invention:

in which R represents hydrogen, a straight or branched chain alkyl group preferably containing 1 to 4 carbon atoms, a substituted or unsubstituted aryl group such as phenyl or tolyl, a cyanoalkyl group such as cyanomethyl, cycanoethyl or cyanopropyl, or the group --CONHR R represents hydrogen, a straight or branched chain alkyl group preferably containing from 1 to 6 carbon atoms, a cycloalkyl group such as cyclopentyl or cyclohexyl, a substituted or unsubstituted aryl group such as phenyl or tolyl or an alkoxy alkyl group such as methoxy methyl;

Z represents acrylic, methacrylic, fumaric or maleic acid or their ammonium or alkali metal salts; acrylamide ormethacrylamide; an N-alkyl (preferably C acrylamide or methacrylamide; an N-hydroxyalkyl acrylamide or methacrylamide such as N-hydroxymethyl acrylamide or methacrylamide an N-oxoalkyl acrylamide or methacrylamide such as diacetone acrylamide; fumaric or maleic acid semiamide or their ammonium or alkali metal salts; a monohydroxyalkyl acrylate or methacrylate such as 2-hydroxyethyl methacrylate; a dihydroxyalkyl acrylate or methacrylate such as 2,2-dihydroxymethyl propyl methacrylate; a dialkylaminoalkyl acrylate or methacrylate such as 2-dimethylaminoethyl methacrylate; a sulfoalkyl carboxylate such as 2-sulfoethyl methacrylate, sulfopropyl methacrylate or sulfopropyl maleate; vinyl pyrrolidone; vinyl caprolactam; vinyl pyridine or vinyl imidazole;

Y represents a polymerisab le group selected from styrene, acrylic acid ,esters such as methyl or ethyl acrylic acid estersand the compound in which R represents an alkyl group, for example a methyl group;

n 5 99.5 mols-% and m 95 0.5 mols-% when p: 0, and

n 5 80 mols-%,

m l0 mols-% and p 45 l0 mols-% when p 9* 0.

methyl-maleic methods from isobutene, acetic acid and oxygen. Its

polymerisation is carried out as a radical polymerisation by means of peroxides (e.g. benzoyl peroxide, di-tert.butyl peroxide, dilauryl peroxide, dicumyl peroxide, tert.butyl hydroperoxide, cumene hydroperoxide or diacetyl peroxide), percarboxylic acid esters (e.g. tert.butyl peracetate, perbenzoate, peroctoate, perpinalate or perisobutyrate), percarbonates (e. g. isopropyl peroxydicarbonate or ethylhexyl percarbonate), acyl sulphonyl peroxides (e.g. acetyl cyclohexane sulphonyl peroxide) or azo compounds. It is carried out in emulsion or in the absence of a solvent and the molecular weights of the polymers determined by osmometric methods of measurement may be from 500 to 3,000. These starting materials are soluble in most organic solvents such as acetone, ether, alcohol, benzene, dioxane, dimethylformamide, dimethylsulphoxide, ethyl acetate, or petroleum ether.

In the second reaction stage, the polymeric acetate is saponified by acid or alkaline saponification. According to a preferred saponification method, for example, poly-l,3-diacetoxy-Z-methylenepropane is dissolved in alcohol and converted into the desired poly-1,3-dihydroxy-2-methylenepropane by the addition of a alcoholic sodium or potassium hydroxide solution at a temperature of between and C. Alternatively, Zemplens alcoholysis method which is known from the chemistry of sugars may be employed, using catalytic quantities of an alkali metal alcoholate. In both cases, the polyalcohol remains in solution and the solution is therefore evaporated to dryness. If it is desired to remove the inorganic acetates present as impurities, the methanolic or aqueous solution of poly-1,3-dihydroxy- Z-methylenepropane may be treated with ion exchangers. The residue obtained after removal of the alcohol used for saponification is then taken up again in a solvent such as dimethylformamide which will not dissolve alkali metal acetates, so that the product can then again be isolated by suction filtration of the salt and evaporation of the solution. According to another saponification method, an alcoholic alkali metal hydroxide is 4 added to the poly-l,3-diacetoxy-Z-methylenepropane dissolved in alcohol/ester to precipitate the poly-1,3- dihydroxy-Z-methylenepropane which is immediately ready for use after removal of the solvent and drying.

Polyethers of formula I can be obtained by reacting the polymeric alcohol with alkylating agents such as diazomethane, dialkyl sulphate or p-toluene sulphonic acid esters or by the addition of acrylonitrile. According to another method of preparing such ethers, the reaction is preceded by the polymerisation of 1,3- dichloro-2-methylenepropane which can be obtained by reacting l,3-dihydroxy-Z-methylenepropane with thionyl chloride or phosgene. The polymer is then reacted with alcoholates.

To obtain polymers of formula II in which R is not CONHR copolymers are first prepared from mixtures of 5 99.5 mols-% of l,3-diacetoxy-2-methylenepropane and 0.5 mols-% of monomers which contain hydrophilic groups such as acrylic or methacrylic acid, itaconic acid, fumaric acid, maleic acid anhydride, acrylamides or methacrylamides, itaconic, fumaric or maleic acid amides or their N-substituted derivatives such as N-alkyl-, N-hydroxyalkylor N-oxoalkylamides, for example N-methyl-(meth) acrylamide, N- acid semiamide, N-hydroxymethyl(meth) acrylamide or diacetone acrylamide; or also N-vinyl pyrrolidone or N-vinyl caprolactam. The copolymers are subsequently saponified with an alcoholic alkali metal alcoholate by Zernplens method or with alcoholic alkali metal hydroxide. In the case of copolymers of l,3-dihydroxy-2-methylenepropane and carboxylates obtained in thsi way which are among the various products which can be obtained, e.g. poly-( 1,3- dihydroxy-2-methylenepropane maleate), a sulpho group may subsequently be introduced by reaction with alkane sultones.

If l,3-diacetoxy-Z-methylene propane and acrylonitrile are copolymerised in a molar ratio of 0.3 l7 99.7 83 in an aqueous suspension with the aid of a redox system such as potassium persulphate/sodium metabisulphite as described in German Pat. Specification No. 2,047,249 and the product is then hydrolysed, a high-molecular weight, water-soluble copolymer is obtained which also contains carboxyl or carboxylate and primary hydroxyl groups as well as containing additional amide groups, depending on the conditions under which the reactions are carried out.

These polymers are comparable in their molecular weights with terpolymers of formula III which are obtained by the alkaline saponification of copolymers, e.g. from styrene, l,3-diacetoxy-Z-methylenepropane and maleic acid anhydride. These starting materials are preferably used in a molar ratio of styrene 1,3- diacetoxy-2-methylenepropane maleic acid anhydride l:l:2 because the best yields and molecular weights are then obtained. The carboxylate functions formed by saponification render the products water-soluble but the water insoluble acids may be prepared from them, and these may then be converted into amides while the remaining acid may be neutralised with an alkali in order to obtain again the required solubility in water.

If one compares the relative viscosities (1 part by weight/ parts by volume of solvent) of the various groups of original polymers which have been obtained preparing the polymers according to the invention, it is found that the terpolymers of formula III have relative viscosities of up to 4.0 and hence the highest molecular weights, followed by the copolymers of formula II 1.3; in the case of the acrylonitrile copolymers mentioned above also 4) while the uni-l,3-diacetoxy-2-methylenepropanes (approximately 1.08) are low-molecular weight compounds a fact which is also confirmed by osmometric determinations. The derived homopolymers of formula I are found to have degrees of polymerisation of from 3 to 20.

l,3-dicarbamoxy-Z-methylenepropane and 1,3-di- (N-alkylcarbamoxy)-2-methylenepropane which are required for preparing the homopolymers or copolymers of formulae I or II in which R =CONHR can be synthesised by converting l,3-dihydroxy-2-methylenepropane into the bis-chloroa carbonic acid ester and then reacting this with ammonia or by an addition reaction of aliphatic, cycloaliphatic or aromatic monoisocyanates with the above-mentioned diol. 1,3- dihydroxy-2-methylenepropane can be obtained by the hydrolysis of 1,3 -diacetoxy-Z-methylenepropane which can in turn be obtained from isobutene, acetic acid and oxygen by methods which have already been described. The addition of the isocyanates is carried out in the absence of solvents or in inert solvents such as benzene, ethyl acetate, chloroform, methylene chloride, or carbon tetrachloride, at room temperature or at boiling point. The dicarbamates separate in the cold and can immediately be isolated in an analytically pure form by suction filtration.

To prepare dicarbamate-type homopolymers of formula I, l,3-dicarbamoxy-2-methylenepropane as well as 1,3-di-N,N-methylcarbamoxy-2-methylenepropane or l,3-di-N,N-ethyl-carbamoxy-2-methylenepropane are polymerised, preferably solvent-free, with peroxides (benzoyl peroxide, di-tertbutyl peroxide, dilauroyl peroxide, dicumyl peroxide, tert.butyl hydroperoxide, cumene hydroperoxide or diacetyl peroxide); percarboxylic acid esters (tert.-butyl peracetate, perbenzoate, peroctoate, perpivalate or perisobutyrate); percarbonates (isopropyl peroxydicarbonate or ethylhexyl percarbonate); acyl sulphonyl peroxides (acetyl cyclohexane sulphonyl peroxide) or azo compounds. The molecular weights of the water-soluble unipolymers determined by osmometric methods are 500 4000. The dicarbamates in some cases separate as oils when their aqueous solutions are heated, but redissolve on coolmg.

The method selected for copolymerising the dicarbamates to polymers of formula 11 is either that of solventfree polymerisation or polymerisation in solvents which may be water, alcohols, ketones, esters, aromatic solvents, N-monoalkylated or dialkylated cyclic lactams, carboxylic acid amides such as N-methyl pyrrolidone, dimethylformamide, dimethyl sulphoxide, glycol carbonate, butyrolactone, etc.. Apart from the starters already mentioned, persulphates, chlorates, etc. may also be used. The following may be used as comonomers for 1,3-dicarbamoxy-2-methylenepropane or 1,3- di-N,N-alkylcarbamoxy-2-methylenepropane: Acrylic and methacrylic acid, acrylamide and methacrylamide, N-hydroxyalkyl acrylamide or methacrylamide, e.g. N-hydroxymethyl acrylamide; N-oxoalkyl acrylamide or methacrylamide such as diacetone acrylamide; fumaric acid, maleic acid and their semi-esters or semiamides (N-alkyl-substituted or unsubstituted), maleic acid anhydride, vinyl pyrrolidone, vinyl caprolactam, monohydroxyalkyl acrylates or methacrylates, e.g. 2- hydroxy-ethyl acrylate, dihydroxyalkyl acrylates or methacrylates, e.g. 2,2-dihydroxymethyl-propyl methacrylate, dialkylaminoalkyl acrylates or methacrylates such as 2-dimethylaminoethyl methacrylate, vinyl pyridines, vinyl imidazoles, and sulphoalkyl acrylates or methacrylates, e.g. 2-sulphoethyl methacrylate.

The preparation of the copolymers of dicarbamates and maleic acid semiesters or amides may also be carried out by subsequently reacting the copolymers of dicarbamates and maleic acid anhydride with alcohols or amines. Furthermore, the free acidic or amino functions of the copolymers may be converted into the salt form. The quantities used are 05-90 mols-% of comonomer and 99.5 mols-% of dicarbamate. The relative viscosities of the copolymers obtained (1 part by weight/ 100 parts by volume of solvent) are from 1.05 to 3.0.

The preparation of the compounds according to the invention will now be explained in detail with the aid of the following examples:

Compound 1:

5.8 mol of 1,3-diacetoxy-2-methylenepropane are started with 0.0274 mol of di-tert.butyl-peroxide at 120-130C with stirring. Almost no exothermic reaction takes place. Further quantities of starter are added at 122l30C as follows: 0.0274 mol after 2 hours, 0.0137 mol after 4 hours and 0.0137 mol after hours. The total polymerisation time is 28 hours. Un-

polymerised monomer is then evaporated off at 12 mm. 0.39 mol are obtained at this stage. No more volatile constituents are then isolated under a high vacuum at 120 130C.

The polymer which remains behind is a clear, pale, highly viscous thermoplastic mass which is soluble in all organic solvents such as acetone, ether, alcohols, benzene, dioxane, dimethylformamide, dimethylsulphoxide, ethyl acetate, or petroleum ether. MW (benzene): 1510 and 1530.

Saponification:

5.4 mol of poly-1,3-diacetoxy-2-methylenepropane are dissolved in a mixture of 800 parts by volume of methanol and 2000 parts by volume of methyl acetate, and 1.75 mol of sodium hydroxide in 700 parts by volume of methanol are added dropwise at room temperature, the polyalcohol then precipitating immediately. The supernatant solvent mixture is decanted off and the residue, which is contaminated with sodium acetate, is dissolved in about 2000 parts by volume of dimethylformamide and suction filtered to remove cloudy impurities. Active charcoal and cation exchanger are then added and the mixture is again filtered and evaporated to dryness under vacuum. Yield: 4.73 mol 416 parts by weight (86 soluble in water, methanol, ethanol, dimethylformamide, and N-methyl pyrrolidone; melting range: 90C; insoluble in n-propanol, ipropanol, acetone, methylene chloride, ethyl acetate, dioxane, benzene and dichlorobenzene. Molecular weight (methanol): 570. A maximum of 5 of ester groups is still visible in the infrared spectrum.

Compound 6: (Poly-1,3-di-N,N-methylcarbamoxy-2- methylenepropane) a. Preparation of the monomer:

4mol of methyl isocyanate are introduced dropwise at room temperature into a solution of 2 mol of l,3-dihydroxy-2-methylenepropane in 750 parts by volume of absolute benzene. The clear solution is heated under reflux for 1 hour. 1,3-di- N,N -methylcarbamoxy-Z-methylenepropane separates on cooling. It is suction-filtered and dried. Yield: 1.84 mol 371 parts by weight (92 MP: 86C

C H N O CNHHN2O4 7: 7c 7: 7:

Calculated; 47.6 7.0 13.9 31 4 Found: 48.0 7.1 13.9 31.7 47.8 13.9 3 l .6

b. Polymerisation:

0.0343 mol of di-tert.butyl peroxide is added to 2.48 mol of the dicarbamate which is then heated to C for 20 hours under an atmosphere of nitrogen with stirring. After the addition of a further portion of 0.0343 mol of the peroxide, stirring is continued at the same temperature for another 8 hours. When cold, the mass is crushed and stirred with ethyl acetate for 1 hour at room temperature. The supernatant ester is then decanted off and the residue dried. Yield: 1.78 mol 360 parts by weight (72 a (1 part by weight/ 100 parts by volume of dimethylforrnamide): 1.05; Molecular weight (methanol): 670. The polymer is soluble in cold water but partly separates as an oil when heated and redissolves on cooling.

Other 1,3-di-N,N'-alkylcarbamoxy-Z-methylenepropanes are prepared by way of example as described above.

Compound 7:( 1,3-di-N,N'-propylcarbamoxy-2- methylenepropane) Yield: 80

Melting point: 83C

Compound 8: (1,3-di-N,N-isopropylcarbamoxy-2- methylenepropane) Yield: 80

Melting point: 109C Compound 9: 1,3-di-N,N-phenylcarbamoxy-2- methylenepropane) Yield: 92

Melting point: 135C Compound 10: methylenepropane) Yield: 80

Melting point: 59C Compound 1 1: l,3-di-N,N'-methoxymethylcarbamoxy-Z-methylenepropane) 1 mol of methoxymethyl isocyanate is added dropwise to 0.5 mol of 1,3-dihydroxy-2-methylenepropane at room temperature. The reaction is exothermic. The mixture is heated for 1 hour at 100C to complete the reaction. No starting materials are recovered when a vacuum is applied. The dicarbamate is originally obtained as an oil which gradually crystallises. Its structure is confirmed by the infra-red spectrum.

Yield: quantitative; Melting point: 30-32C 1 ,3 -di-N,N'-butylcarbamoxy-2- Compound 12:

6.75 mol of N-vinyl pyrrolidone and 1.45 mol of 1,3-diacetoxy-2-methylenepropane are taken up in 2,500 parts by volume of benzene and heated to boiling with stirring. 0.0305 mol of azo-bisisobutyronitrile dissolved in 100 parts by volume of benzene is introduced dropwise into the boiling solution. The solution is then heated for another 8 hours under reflux. When the solution is cool, it is poured into about 5,000 parts by volume of petroleum ether with vigorous stirring, the copolymer formed in the reaction thereby precipitating. It is suction-filtered, washed with petroleum ether and dried. The yield is 975 parts by weight (97.5 a (1 part by weight/100 parts by volume of dimethylformamide): 1.23. Elementary analysis shows that the copolymer contains 76.7 mols-% of N-vinyl pyrrolidone. Its melting range is 170 200C. An infra-red spectrum shows the ester band at 1,750 cm and the cyclic amide function at 1,670 cm. The copolymer is then dissolved in 2,200 parts by volume of anhydrous methanol with stirring and 60 parts by volume of a 10 sodium methylate solution are intro duced. The reaction mixture is left to stand at room temperature for 12 hours and then evaporated to dryness under vacuum. A syrup remained from which the remaining quantities of methanol are removed by drying at elevated temperature. 820 parts by weight of a pale product which has a melting range of 220 280C and a viscosity of m 1= 1.20 are obtained. Elementary analysis shows the product to contain mols-% of N-vinyl pyrrolidone. An infra-red spectrum shows that the ester function at 1,750 cm has been extinguished by alcoholysis.

Compound 13:

0.405 mol of N-vinyl pyrrolidone and 0.61 mol of 1,3-

diacetoxy-2-methylenepropane are heated to C and 0.00343 mol of di-tert.-bu'tyl peroxide are added. After a reaction time of 2 hours, another 0.00343 mol of the peroxide are added and this is repeated after 4 hours. The total polymerisation time is 8 hours at 130 C. When cold, the viscous mass is taken up in benzene and precipitated with petroleum ether. By working up and drying the product in this way, 125 parts by weight (83.5 are isolated. It has a relative viscosity of a 1.08 (1 part by weight/100 parts by volume of dimethylformamide) and contains 41.8 mol-% of N-vinyl pyrrolidone. Alcoholysis is carried out as already described.

Compound 15:

2.5 mol of l,3-diacetoxy-2-melthylenepropane and 2.5 mol of maleic acid anhydride are dissolved in 1,200 parts by volume of ethyl acetate. 0.0695 mol of ten.- butyl peroctoate is added to the solution which is then heated to boiling for 6 hours with stirring. The solution is then cooled and the copolymer is precipitated by pouring the viscous solution into twice its volume of benzene. After suction filtration, washing and drying, the yield of copolymer is 2.26 mol 610 parts by weight (91 n 1.1 (1 part by weight/100 parts by volume of dimethylformamide); melting range C. To convert the product into the disodium salt of poly-l,3-dihydroxy-Z-methylenepropane maleic acid, 1.85 mol of copolymer are introduced into a solution of 5 mol of sodium hydroxide in 2,000 parts by volume of methanol and heated under reflux for 6 hours with stirring. The reaction mixture is then suction-filtered and dried. The yield is 1.71 mol (91.5 Compound 18:

0.3 mol of the disodium salt of poly-1,3-dihydroxy-2- methylenepropane-maleic acid (compound 15) are suspended in 300 parts by volume of ethanol, and, after the addition of 0.3 mol of propane sultone, the suspension is heated under reflux for 12 hours with stirring. It is then suctionfiltered while hot, washed with ethanol and dried. Yield: 97 parts by weight (87 Analysis: S calculated 8.64 (conversion to a carboxylate function) Found: 7.25. This means that 42% of the carboxylate functions have been esterified.

Compound 21:

(Copolymer of 1,3-di-N,N-methy1-carbamoxy-2- methylenepropane and methacrylic acid) 0.248 mol of 1,3-di-N,N-methyl-carbamoxy-2- methylenepropane, 0.582 mol of partly distilled methacrylic acid and 0.00463 mol of tert.-buty1 peroctoate are introduced into 250 parts by volume of i-propanol and the mixture is heated to boiling for 6 hours with stirring. When cooled, the viscous solution is poured into 3,000 parts by volume of ethyl acetate and the precipitated copolymer is suction-filtered and dried.

methylformamide). Elementary nitrogen analysis shows that the water soluble polymer contains 17.6

mols-% of 1 ,3-di-N,N'-methyl-carbamoxy-2- methylenepropane. Compound 22:

(Copolymer of l,3-di-N,N-methyl-carbamoxy-2- methylenepropane and acrylic acid) 0.248 mol of the dicarbamate and 0.695 mol of the acid are treated and worked up as in the previous example. Yield: 78 parts by weight (78 17 1.29. The acrylic acid content of the water-soluble polymer is found to be 7.3 mols-% by titration with sodium hydroxide.

Compound 23:

(Copolymer of l,3-di-N,N'-methyl-carbamoxy-2- methylenepropane and methacrylamide) 1.24 mol of the dicarbamate and 2.94 mol of methacrylamide in 1,250 parts by volume of water are heated to 70 75C and 0.022 mol of ammonium persulphate are added. The reaction mixture is stirred at this temperature for 8 hours and part of the water is then evaporated off under vacuum. The copolymer is precipitated by pouring its aqueous solution into about 10,000 parts by volume of methanol. 310 parts by weight (62 of the polymer remain after suctionfiltration, washing and drying. 1t decomposes at 240 250C and has a relative viscosity of 1;, 1.25 1 part by weight/ 100 parts by volume of water).

Compound 26:

(Copolymer of l,3-di-N,N-methyl-carbamoxy-2- methylenepropane and maleic acid anhydride) 0.5 mol of the dicarbamate and 0.5 mol of the acid anhydride in 450 parts by volume of benzene are disl,3-di-N,N'-propyl-carbamoxy-2- method similar to that employed in the previous example.

Yield: 0.46 mol 163 parts by weight (92 Mp: 130 160C.

Compound 29:

0.5 mol of styrene, 0.5 mol of 1,3-diacetoxy-2- methylenepropane and 1 mol of maleic acid anhydride are dissolved in 900 parts by volume of benzene by heating and stirring. Polymerisation is initiated at boiling point by the addition of 0.0115 mol of tert.butyl peroctoate. The reaction mixture is boiled under reflux for 7 hours and the precipitated polymer is then suction-filtered, washed and dried.

Yield: 186 parts by weight (77 I 1p (1 part by weight/ 100 parts by volume of dimethylformamide): 2.1;

Melting range: 205 220C.

16 To saponify the polymer, it is introduced into a solution of 2.25 mol of sodium hydroxide in 600 parts by volume of methanol and boiled under reflux for 6 hours with stirring reaction product is then suction-filtered and dried.

Yield: I l parts by weight.

Compared with other polymer compounds such as with gelatine in the solid state. It is known that polyvi nyl alcohol is incompatible with gelatine when added in quantities of more than 5 Although the basic unit CHEOH cn on is very similar to the basic vinyl alcohol unit and from a formal point of view constitutes a dimer of the vinyl alcohol, the two polymers differ in their properties. It was not foreseeable that they would also differ from each other in photographic respects. Polyvinyl alcohol is inert in photographic emulsions.

The polymers to be used according to the invention have the advantage over many of the known stabilisers that they have an excellent stabilising effect on the photographic properties such as sensitivity, gradation and clarity and if anything improve the graininess of the emulsions. 1f the compounds are added to the emulsion before chemical after-ripening, greater sensitivity can be obtained for the same amount of fogging.

Many stabilisers which are particularly effective in preventing an increase in fogging also reduce the sensitivity compared with the sensitivity of the fresh sample. Other stabilisers which achieve a tolerable stability of the fogging values cause a more or less substantial but, in all cases, undesirable change in the sensitivity if used during storage, and this is in most cases accompanied by a flattening of the gradation. By contrast, the polymers mentioned here have an excellentstabilising effect both on the clarity and on the gradation and sensitivity so that these properties remain unchanged over long periods of time.

The polymers to be used according to the invention may be added to the usual photographic layers, that is to say tolayers used in general for photographic materials such as light-sensitive silver halide emulsion layers, protective layers, filter layers, antihalation layers, back coatings, baryta layers or, in general, any photographic auxiliary layers. 1 The light-sensitive emulsion layers to which the polymers may be added may be, for example, layers which are based on emulsions which have not been sensitised or on orthochromatic, panchromatic or infraredemul- 'sions, X-ray emulsions or other s'pectrally sensitised emulsions. The layersused for various black-and-white and colour photographic processes are also suitable.

The polymers have been found to be particularly advantag eous for use in photographic layer combinations used for carrying out colour photographic processes, for example those which containemulsion layers with colour couplers or emulsion layers which are to be treated with solutions which contain colour couplers.

These compounds may be added to the light-sensitive silver halide emulsions at any stage of the preparation of the emulsions but they are preferably added as casting additive before the stage of after-ripening. The quantity added may vary within wide limits but quantities of 50 g per mol of silver halide have generally been found to be sufficient. Particularly good results are obtained if the emulsions contain from 20 30 g of the compounds according to the invention per mol of silver halide.

The compounds according to the invention are advantageously added in the form of solutions. Water is a suitable solvent for this purpose.

The usual silver halide emulsions are suitable for this invention. The silver halide contained in these emulsions may be silver chloride, silver bromide or mixtures thereof, which may have a small silver iodide content of up to mols The binder used for the photographic layers is preferably gelatine although this may be partly or completely replaced by other natural or synthetic binder. The following are examples of suitable natural binders: Alginic acid and its derivatives such as salts, esters or amides; cellulose derivatives such as carboxymethyl cellulose; hydroalkyl celluloses such as hydroxyethyl cellulose; starch or derivatives thereof such as ethers or esters or carrageenates. Suitable synthetic binders are, for example, polyvinyl alcohol, partly saponified polyvinyl acetate, and polyvinyl pyrrolidone.

The emulsions may also be chemically sensitised, e.g. by adding sulphur compounds such as allyl isothiocyanate, allyl thiourea, and sodium thiosulfate at the chemical ripening stage. Reducing agents may also be used as chemical sensitisers, e.g. the tin compounds described in Belgian Pat. Specifications Nos. 493,464 and 568,687 or polyamines such as diethylenetriamine or aminomethyl sulphinic acid derivatives, e.g. according to Belgian Pat. Specification No. 547,323.

Noble metals such as gold, platinum, palladium, iridium, ruthenium or rhodium and compounds of these metals are also suitable chemical sensitisers. This method of chemical sensitisation has been described in the article by R. Koslowsky, Z. Wiss. Phot. 46, 65 72 (1951).

The emulsions may also be sensitised with polyalkylene oxide derivatives, e.g. with a polyethylene oxide which has a molecular weight of between 1000 and 20,000, or with condensation products of alkylene oxides and aliphatic alcohols, glycols, cyclic dehydration products of hexitols, with alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides. The condensation products should have a molecular weight of at least 700 and preferably more than 1000. These sensitisers may, of course, be combined to achieve special effects, as described in Belgian Pat. Specification No. 537,278 and in British Patent Specification No. 727,982.

The emulsions may also be optically sensitised, e.g. with the usual polymethine dyes such as neutrocyanines, basic or acid carbocyanines, rhodacyanines, hemicyanines, styryl dyes, and oxonoles. Sensitisers of this kind have been described in the work by vF.M. Hamer The'Cyanine Dyes and related Compounds (1964).

In addition to containing the polymers according to the invention, the emulsions may contain other known stabilisers, e.g. homopolar or salt-type compounds of mercury which contain aromatic or heterocyclic rings such as mercaptotriazoles, simple mercury salts, sulphonium mercury double salts and other mercury compounds. Other suitable stabilisers include azaindenes, particularly tetraor pentaaza'indenes and especially those which are substituted with hydroxyl or amino groups. Compounds of this kind. have been described in the article by Birr, Z. Wiss. Phot. 47, 2 58 (1952). Other suitable stabilisers are, among others, heterocyclic mercapto compounds, e.g. phenyl mercaptotetrazole, quaternary benzothiazole derivatives, and benzotriazole.

The emulsions may be hardened in the usual manner, for example with formaldehyde or halogenated aldehydes which contain a carboxyl group such as mucobromic acid, diketones, methane sulphonic acid esters, and dialdehydes.

The emulsions may also contain colour couplers in the form of solutions or dispersions.

EXAMPLE 1 A maximum sensitivity silver iodobromide gelatine emulsion containing 6 mols-% of silver iodide was prepared in the usual manner by running the silver nitrate solution at intervals into a solution which contained gelatine in addition to potassium bromide and iodide. The emulsion was flocculated in known manner with ammonium sulfate and freed from the soluble salts. The flocculate was redispersed in warm water, ripening gelatin which contains sulfur was added and the dispersion was ripened to optimum sensitivity in the presence of gold(I) thiocyanate complexes and sodium thiosulfate. The finished emulsion contained 54 g of silver per kg in the form of silver halide.

After chemical ripening of the emulsion, 600 mg of saponin were added as wetting agent and 10 ml of a 10 aqueous solution of formaldehyde, based in each case on 1 kg of emulsion.

Before the emulsion was cast, it was divided into 12 portions, one portion remaining without additive while to the other portions, which serve as samples 1 to l l, were added the compounds Nos. 1, 6, l2, l3, l4, 19, 20, 22, 23, 29 and 30.

The samples were then cast on a cellulose acetate substrate and dried, exposed to a sensitometer behind a grey step wedge and developed at 20C for 7 minutes and 16 minutes, respectively, in a developer of the following composition:

. T'P P39. ACUI utco auoeoo anuaau The results of sensitometric determination are shown in the following table:

Table I Com Quantity in 7 minutes development time 16 minutes development time pound No. g/kg of emulsion Sensitivity Gradation Fog Sensitivity Grudation Fog without additive 1.20 0.23 blank 1.35 0.32 l +0.5 1.15 0.15 +1.0 1.35 0.27 6 3 +0.5 1.25 0.19 +0.5 1.40 0.28 l2 18 10 1.25 0.19 +1.0" 1.40 0.28 13 20 1.20 0.17 i0 1.35 0.25 14 20 +0.5 1.25 0.12 20 1.40 0.19 19 20 1.0 1.25 0.11 +O.5 1.35 0.17 20 20 1.20 0.11 +1.0 1.40 0.16 22 8 I 0 1.25 0.20 i0 1.35 0.29 23 10 10 1.25 0.18 +I.0 1.40 0.27 29 0.5" 1.20 0.18 10 1.30 0.25 30 18 1.0" 1.30 0.19 +O.5 1.45 0.29

Concerning the figures for sensitivity given in the table.

3 units 1 Shutter stop 0.3 log. l.t

As can be seen from the table, with the same value and in some cases a sensitivity increased by 0.5-1 DIN, a distinct reduction in fog was obtained, both with 7 and with 16 minutes development.

EXAMPLE ,2

A highly sensitive silver iodobromide gelatine emulsion containing 5 mols-% of silver iodide was prepared as described in Example 1. 30

Before the emulsion was cast, it was divided into 5 portions, one being left as sample without additive f o while compounds 1, 12, 20 and 29 were added to the N four other samples. 0 H

The samples were cast on a support layer of cellulose 5 N triacetate, dried, exposed behind a grey step wedge in a l sensitometer and developed for 7 minutes and 16 min- S o H utes at 20C in the developer described in Example 1. 3

The following table shows the results of the sensitometric determinations. It can be seen that marked sta- 40 bilization of the fog was obtained even when the emulso H sion was stored in a heating cupboard at C. 3

Table I1 Com- Quantity in 7 minutes development 16 minutes development 5 days in drying cupboard lil i g/kg of time time 16 minutes development time emulsion Sensitivity Gradation Fog Sensitivity Gradation Fog Sensitivity Gradation Fog without 0.30 additive 1.15 0.22 blank 1.30 0.30 +0.5 1.35 0.30 1 20 +0.5 1.10 0.13 +0.5 1.20 0.24 +1.0 1.30 0.29 12 20 +1.0 1.20 0.17 +0.5 1.25 0.26 +0.5 1.30 0.30 20 20 +0.5 1.15 0.11 +0.5 1.30 0.17 +1 0' 1.35 0.25 29 20 :0 1.10 0.18 10 1.20 0.27 +0.5 1.25 0.20

r 55 EXAMPLE 3 were added.

25 ml of a l methanolic solution of 4-hydroxy-6- 20 g of the coupler methyl-1,3,3.a,7-tetraazaindene, 30 ml of a 10 aque- OH ous saponin solution and 15 ml of a 0.5 aqueous I 6O chromacetate solution were added to the emulsion 4 4 2 H t which now contains coupler and masking coupler, and 1 1 g 5 H the emulsion was cast on a support layer of cellulose triacetate to form a layer of about 4.5 ,u. in thickness.

1 t The pH of the layer is about 6.5-7.

After drying, the material was exposed behind a continuous wedge and developed in a developer of the following composition for 15 minutes:

g of 2-amino-5-( N-ethyl-N-B-methane sulphonamidoethylamino )-toluene sesquisulphate monohydrate,

5 ml of benzyl alcohol,

2.5 g of sodium hexametaphosphate,

1.85 g of sodium sulphite sicc.

1.4 g of sodium bromide,

0.5 mg of potassium iodide,

12.5 g of sodium hydroxide and 34.22 g of Na B O .5H O made up to 1 l with water.

The emulsion was then treated with the following baths: Short stop bath 17 ml of glacial acetic acid 2.94 g of sodium acetate sicc.

water up to l l.

Hardening bath 0.3 g of sodium hydroxide 0.5 g of sodium hexametaphosphate 9.04 g of soda 20 ml of 37 formalin water up to l l.

Bleaching bath 6 g of sodium hexametaphosphate 42.0 g of potassium ferricyanide 12.0 g of potassium bromide.

6.0 g of disodium phosphate 16.0 g of mono-potassium phosphate water up to l l.

Fixing bath 150 g of ammonium thiosulphate g of sodium sulphite water up to l 1.

Final bath 0.3 g of sodium tetrapropylene benzene sulphonate water up to 1000 ml.

The treatment times after development are as follows:

Short stop bath 4 minutes hardening bath 4 minutes washing 5 minutes bleaching bath 6 minutes washing 5 minutes fixing bath 8 minutes washing 10 minutes final bath 30 seconds.

A cyan dye was formed in the exposed areas and the orange red masking dye was preserved in the unexposed areas. Sensitometric determination shows that excellent masking of the material is obtained in the blue and green ranges of measurement.

B. (based on gelatine) of compound 1 were added as casting additive to a second sample.

The following fogging values were obtained for the two samples:

The sensitivity of sample B is l.5 higher than that of A.

We claim:

1. A light-sensitive photographic material containing at least one silver halide emulsion layer, said emulsion layer containing at least one compound of the formulae:

ill

in which R, represents H, alkyl, aryl, cyanoalkyl or -CO- NHR R represents H, alkyl, cyc'loalkyl, aryl or alkoxy alkyl,

Z represents acrylic, methacrylic, fumaric or maleic acid groups, optionally in a salt form, an N-alkyl-, N-hydroxyalkylor N-oxoalkyl acrylamide or methacrylamide group, furmaric or maleic acid semiamide optionally in a salt form, monoor dihydroxyalkyl acrylate or methacrylate, sulphoalkyl acrylate or methacrylate, or vinyl-pyrrolidone, -caprolactam, -piperidine or -imidazole,

Y polymerisable group selected from styrene,

acrylic acid esters or wherein R represents methyl or ethyl,

n 5 99.5 mols-% and m 95 0.5 mols-% when p 0 and n 5 mols-%,

m 50 l0 mols-% and p 45 l0 mols-% when p 0.

2. Light-sensitive photographic material according to claim 1, characterised in that it contains poly-1,3- diacetoxy-2-methylenepropane.

3. Light-sensitive photographic material according to claim 1, characterised in that it contains poly-1 ,3-diN,- N'-methyl-carbamoxy-2-methylenepropane.

4. Light-sensitive photographic material according to claim 1, characterised in that it contains a copolymer of the formula wherein 35 mols-% and m 65 mols-%.

5. Light-sensitive photographic material according to claim 1, characterised in that it contains a polymer of the formula OONu CO-NH wherein n 5 80 mols-%, m 10 50 mols-% and p 10 45 mols-%. 

1. A LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL CONTAINING AT LEAST ONE SILVER HALIDE EMULSION LAYER, SAID EMULSION LAYER CONTAINING AT LEAST ONE COMPOUND OF THE FORMULAE:
 2. Light-sensitive photographic material according to claim 1, characterised in that it contains poly-1,3-diacetoxy-2-methylenepropane.
 3. Light-sensitive photographic material according to claim 1, characterised in that it contains poly-1,3-diN,N''-methyl-carbamoxy-2-methylenepropane.
 4. Light-sensitive photographic material according to claim 1, characterised in that it contains a copolymer of the formula
 5. Light-sensitive photographic material according to claim 1, characterised in that it contains a polymer of the formula 